Currently, touch panel displays have been developed rapidly, and have become the mainstream of the flat panel displays gradually. A sectional view of a pixel region and a peripheral drive region of a touch panel is shown in FIG. 1, and the touch panel comprises a pattern of a metal connecting layer 4 formed on a substrate 7, a pattern of an insulating layer 5 on the pattern of the metal connecting layer 4, a pattern of a driving electrode 2 that is provided on the pattern of the insulating layer 5 and is connected to the pattern of the metal connecting layer 4 through a via-hole in the pattern of the insulating layer 5, a pattern of a sensing electrode 1 on the pattern of the insulating layer 5, and a pattern of a protective layer 6 that is provided to cover the pattern of the driving electrode 2 and the pattern of the sensing electrode 1. A via-hole is formed in the protective layer 6 in the peripheral drive region, so that the driving electrode 2 exposed by the via-hole is connected to a peripheral drive circuit (not shown); there is no via-hole in the protective layer 6 in the pixel region, and a downward concave happens to the protective layer 6 in the region as shown in FIG. 1. The reason for this is that there are steps in the level (the lower level) under the protective layer 6, and thus the protective layer 6 in the pixel region will be concaved downward to a certain degree.
The manufacturing process of the above touch panel is usually as follows.
Firstly, a layer of metal thin film is formed on a substrate and patterned with a mask so as to form pattern of a metal connecting layer 4.
Secondly, a layer of non-metal thin film is deposited on the substrate 7 with pattern of the metal connecting layer 4 formed thereon, and is patterned with a mask so as to form the pattern of an insulating layer 5; a via-hole in the insulating layer 5 in the pixel region is smaller, and a via-hole in the insulating layer 5 in the peripheral drive region is relatively larger.
Next, a layer of thin film of a transparent conductive material is formed on the substrate further, and is patterned to form the pattern of a driving electrode 2 and the pattern of a sensing electrode 1 through a mask.
Finally, a layer of non-metal thin film is formed, and subjected to an exposure and development process with a mask, and etched to form a pattern of a protective layer 6. Here, the portion of the mask corresponding to the pixel region of the substrate is light-proof, and only the portion of the mask corresponding to the peripheral drive region of the substrate is transparent to light.
As can be seen, four masks are demanded in the manufacturing procedure of the above touch panel for patterning processes, the number of required masks is larger, and the production cost is relatively high.